Polyolefin-white pigment composition stabilized with mixtures of a fatty acid and an ultraviolet light stabilizer



' 3 ,444,1 l5 1C6 Patented May 13, 1969 United States Patent 3444 115known in the art which are effective in white polymer POLYOLEFIN WHTi EhGMENT COMPOSL compositions and includes preferably 2-hydroxy-4-n- TIONSTABILIZED WITH MIXTURES 0F octoxybenzophenone. Other compounds whichare useful A FATTY ACID AND AN ULTRAVIOLET are phenol-nickel complexes,phenyl salicylates, alkyl LIGHT STABILIZER phenyl salicylates,benzotriazoles, 2,4-d1-hydroxybenzo- Donald G. Needham, Ramona, andGeorge R. Hill, phenone, z-hy r yy n p en n and the Bartlesville, 0kla.,assignors to Phillips Petroleum like. P y, 'P of Delaware In addition,the composition can also contain other No -115 3 sggf j/ oa 467,135ingredients normally employed to give desirable properties U S Cl 260232 Claims 10 to the resulting polymer. Such ingredients includeantistatic agents, antioxidants, crystallization modifiers, lubricants,dispersing agents, fillers and pigments, and the like.

The following example is presented to further illustrate the invention:

ABSTRACT OF THE DISCLOSURE Polymeric compositions free fromdiscoloration are 5 provided by the addition of an inhibiting amount ofa long chain fatty acid to the pigmented polymer, A series ofcompositions were prepared by simultaneously milling on a roll mill at300 F. for a period of 10 minutes a polyethylene polymer, 2 weightpercent titanium This invention relates to a novel stabilized polymericdioxide, .1 Weight percent of a fatty acid and an ultracomposition and amethod of stabilizing same. In one violet stabilizer. The followingresults were obtained:

Example UV T102, Run Polymer stabilizer percent Fatty acid Color 1Polyethylene UV 531 2 None Yellow, 2 do UV 531 2 Stearic White, 3 do UV531 2 Heptadecanoic Very white.

1 Ethylene-butenc-l copolymer produced by a solution process containingabout 5% butane-1, having a density of 0.95 and a melt index of .2.

2 Z-hydroxy-d-n-octoxybenzophenone.

aspect, this invention relates to color stabilized polymers. The abovedata clearly demonstrate that adverse color In another aspect, thisinvention relates to polymer comdevelopment in white pigmented polymeris achieved by positions of l-olefins in which discoloration isinhibited. the incorporation of the fatty acid into the polymeric Afurther aspect of this invention relates to a method of composition.

inhibiting discoloration in polymers. The long chain fatty acid can bepresent in an amount Polymers of l-olefins, such as polyethylene andpolyin the range of 0.01 to 1.0 percent and preferably about propylene,are suitable for many uses. When such ma- 0.1 percent.

terials are to be used outdoors, it is generally preferred Polymerscapable of being inhibited in accordance with to add an ultravioletlight absorber to the polymer so as this invention are those ofmono-l-olefins having 2 to 8 to extend the outdoor life thereof.However, where a carbon atoms and which are generally formed inamannerwhite polymer is desired for outdoor use, difficulty is enknown in theart, Polymers such as prepared in accordcountered since there isapparently a reaction between the ance with Hogan et al., US. Patent2,825,721, are preconventionally employed white pigment-titanium dioxideferred as well as copolymers thereof such as ethyleneand the ultravioletlight absorber. The resulting composibutene:1. tion turns to a creamcolored off-white. Additives suitable for lnhibltlng the discoloratlonof It is thus an object of this invention to provide a colorthe polymersare monobasic long chain fatty acids constable white polyolefincomposition. taining 10 to 24 carbon atoms. Examples of such com-Another object of this invention is to provide a method pounds includecapric, stearic, lauric, lignoceric, palmitic, for inhibitingdiscoloration in polymers of l-olefins. decylenic, dodecylenic,nervonic, linolenic, oleic acid, and

Other aspects, objects and the several advantages of the like. I thisinvention will be apparent from the following specifi- While anyconventional ultraviolet stabilizer can be emti nd l i ployed in thepolyolefin compositions, it has been found In accordance with thisinvention, we have discovered in accordance with this invention thatmaximum inhibitathat conventionally prepared white polymers of l-olefinstion of discoloration of pigmented polymer 1s achieved in can berendered stable to discoloration by incorporating these compositionswhere 2-hydroxy-4-n-octoxybenzophetherein a long chain fatty acid having10 to 24 carbon none is the stabilizer.

atoms. Reasonable variations and modifications of this inven- The termfiiltraviolet stabilizers as employed herein tion can be made, orfollowed, in view of the foregoing,

is intended to include all known ultraviolet stabilizers withoutdeparting from the spirit or scope thereof.

3 4 We claim: 2,655,492 10/1953 Young et al 260-23 1. A stabilized whitepigment containing polymeric 2,708,215 5/1955 Kaganoff 260-23composition free from discoloration comprising (a) a ,0 7, 8 1/ 1962 Lvine ct a1 26023 polymer of a mono-l-olefin having 2 to 8 carbon atoms,3,188,298 6/ 1965 Williamson et 3 (b) an ultraviolet light stabilizer,(c) from 0.01 to 1.0 5 3,324,060 6/1967 PP et 260-23 weight percent ofthe polymer present of a monobasic 3325/141 6/1967 MCNaHY a] 26041 longchain fatty acid containing 10 to 24 carbon atoms OTHER REFERENCES and(d) a White pigment.

2. A composition according to claim 1 wherein said MartillovichiflasticsTechnology, Better 'Polyolefin polymer is polyethylene, Said Whitepigment is titanium 10 UV. Resistance, vol. 9, November 1963, pages 45and 46.

oxide, said monobasic long chain fatty acid is stearic acid DONALD.CZAJA Primary Examiner and said ultraviolet light stabilizer is2-hydroXy-4-nocroxybenzophenone, R. A. WHITE, Assistant Examiner.

References Cited 15 US. Cl. X.R. UNITED STATES PATENTS 26041, 45.75,45.8, 45.85, 45.95 2,462,331 2/1949 Myers 26023

